REMAINING (number with state)Abdomen, T1, hair color on the dorsal face - This includes very short hairs 2. Mixed light and dark hairs - With yellow hairs found along the base and blackish hairs found along the apical rim (16) 1. All light - The hairs are pale, whitish to yellowish (9) 3. All dark - Note that often there may be some degree of light hair present on the vertical face of T1 which faces the propodeum (8)Abdomen, T2, hair color on the DORSAL face - This does not include hairs found on the lower edge of the sides 1. All dark (24) 2. Mixed light and dark - There are both light and dark hairs present on T2, although they may be very short and somewhat hard to identify as a result (8) 3. All light (6)Abdomen, T5, hair color - Be sure not to confuse hairs arising from the sterna for those of T5 1. All dark (19) 2. Intermixed - There are both light and dark hairs throughout (8) 3. All light - Sometimes the rim has more orangish hairs that contrast with the lighter basal hairs (8)Abdomen, integumental color, NOT hair color - Note, if more than one feature is present then pick whichever is dominant 1. Black to dark reddish brown (22) 2. With very strong METALLIC BLUE tinting, although in later terga this may be obscured by hairs (8) 3. Strongly reddened - Either entirely or primarily an orangish-red color (3) 4. Light integumental markings - With extensive yellowish markings on the terga (2)Abdomen, pygidial plate, shape of apex 3. Convex, usually roundedly (20) 2. Straight, with clear corners, although sometimes there is a very weak indentation medially (17) 1. Concave (3)Abdomen, pygidial plate, shape of the medial ridge on its surface 1. The raised portion of the pygidial plate does not reach the tip of the pygidial plate and is usually triangular, the tip terminating usually approximately halfway down the plate or earlier - Note that specimens which appear to have no raised area should be scored for this state, as quite often the pygidial plate is hidden by the proceeding tergite (23) 2. Taking the form of a long, rounded ridge which travels from the base to the apex with the sides remaining nearly parallel, except at the base and the tip where it may flare out (5)Abdomen, sterna, hair color of the long hairs of S2-4 found along the rim and sometimes centrally 3. All dark (17) 1. All light (9) 2. Mixed light and dark hairs (5)Body length in mm, when measured from tip of abdomen to front of head 15 (23) 16 (22) 14 (21) 13 (17) 17 (17) 12 (13) 18 (13) 19 (10) 11 (9) 20 (9) 10 (5) 21 (5) 22 (4) 23 (3) 24 (2) 9 (1)C. angustifrons vs C. lanosa C. angustifrons - The unpitted medial line on the clypeus is much wider, usually taking up around one-fifth the width of the clypeus, although sometimes it may be irregularly constricted medially by uneven integument that appears more craggy than pitted - On the basitibial plate, there is a raised platform that is restricted to the basal half and although elongate its edge DOES NOT extend along the edge of the basitibial plate past the midpoint in the form of a ridge separating the edge of the plate from the inner surface - In general, this species is usually larger (1) C. lanosa - The unpitted medial line on the clypeus is much narrower, taking up less than a tenth of the width of the clypeus - The basal, raised platform of the basitibial plate extends past the midpoint of its length in the form of a ridge that divides the edge from the interior of the plate - In general, this species is usually smaller (1)C. aterrima vs C. nigrocaerulea - Careful, this is a relatively difficult to distinguish species pair when not using size C. aterrima - The integument of T2 is almost entirely unmarked by microscopic lines, appearing very smooth and shiny and highly reflective as a result - The hairs of T2 are shorter and lie relatively flat upon the surface, the pits that these hair arise from are small in relationship to the width of the hairs make the hairs stand out even more - In general, this species is smaller, usually about 15mm in length (1) C. nigrocaerulea - The integument of T2 is notably more marked by microscopic lines, although it still appears slightly reflective it is much less so than in C. aterrima - The hairs of T2 are larger and suberect in orientation, although they are only readily visible when viewed from the side due to the large size of the pits from which they arise and the granular appearance of the surface integument - In general, this species is larger, usually 18mm or greater in length (1)C. atripes vs C. cockerelli C. atripes - The light integument of the clypeus is almost always tridentate at the top near the supraclypeus, by virtue of there being a large single tip and then one weaker, branched maculation off to each side also pointed upward toward the supraclypeus - There are almost always metallic blue reflections on the terga, making the black hairs there more apparent - T1 has more plumose, more obvious light hairs centrally - The integument of the mandible is usually darker, black to a deep browned red color (1) C. cockerelli - The light integument of the clypeus is relatively formless, usually with areas of dark integument along the lateral and sometimes upper border, and no specimens have been seen with a tridentate top as in C. atripes - There are never metallic blue reflections on the terga, usually making the black hairs relatively difficult to see - T1 has less plumose, more obscure light hairs centrally - The integument of the mandible is usually lighter, with distinctive orangish yellow tints (1)C. caesalpiniae vs C. cockerelli vs C. rhodopus C. caesalpiniae - There is usually a linear patch of light reddish integument running along the back of the compound eye near its top - The clypeus is very sparsely pitted, interspaces most often exceeding three pit diameters with up to five pit diameter interspaces not uncommon - The integument of the femur is only very slightly reddened, if at all, if the femur has a reddish component it is DARK BRICK RED - This species is ALMOST ALWAYS much larger than the other species, about 18mm or longer in total length (1) C. cockerelli - There is ALMOST NEVER a linear patch of light reddish integument present along the back of the compound eye near the top - The clypeus is relatively more densely pitted, interspaces rarely if ever exceeding two pit diameters - The integument of the femurs is only very slightly reddened, if at all, if the femur has a reddish component it is DARK BRICK RED - This species is smaller, averaging about 14mm in total length (1) C. rhodopus - There is usually a linear patch of light reddish integument running along the back of the compound eye near its top - The clypeus is moderately pitted, interspaces usually about equal to 2-3 pit diameters although in some specimens it is as dense as seen in C. cockerelli - The integument of all femurs is strongly reddened, with a light reddish color with little, if any, hint of brown, this is often apparent in a top-down view of the specimen without use of a microscope - This species is of moderate size, averaging about 15-16mm in total length (1)C. nitida vs C. transversa C. nitida - The hair of S4 is all black or nearly so - The hair of the scutum is a typically a bright mustard yellow, sometimes rather dark yellow - This species is larger on average, about 14-15mm in total body length (1) C. transversa - The hair of S4 is black centrally, with distinct white tufts laterally - The hair of the scutum is at most weakly yellow, much more tan or light brown - This species is smaller on average, about 13mm in total body length (1)Head, antennae, length of first flagellar segment 2. Moderate - CLEARLY longer than F2-3 but usually shorter than F2-4, sometimes about equal (27) 3. Long - Greater than F2-4 (15) 1. Short - Equal in length to F2-3 or shorter (12)Head, clypeus, color of light integumental markings - Do not score for this character if no light integumental markings are present - DO NOT score if reddening appears to be a result of cyanide overexposure 1. Pale - Whitish to yellowish (14) 2. Reddish - Orangish to reddish (5)Head, clypeus, integumental luster 1. Shiny - There are no microscopic inscribed markings present, USUALLY leaving the integument highly reflective although nectar or debris may obscure this (26) 2. Dull - Shagreened by fingerprint-like microscopic lines, note that the surface is often still somewhat reflective, but less so (17)Head, clypeus, presence and form of a longitudinal unpitted line running down the center 2. Present, weak - Pitting is clearly sparser medially, but heavy pitting above and below this central area prevents the formation of a complete longitudinal band - Note that in these species the longitudinal unpitted line is usually thinner than in those exhibiting the strong state (23) 3. Present, strong - There is a broad and well-defined unpitted area running longitudinally down the center of the clypeus, which, if bounded at all by pitting above or below, is only very slightly so (20) 1. Absent - Pit density roughly the same throughout the clypeus (13)Head, clypeus, presence and form of light integumental markings 1. Entirely dark - Dark brown to blackish (15) 2. Primarily dark - There is some light integument present on the clypeus, usually taking place primarily in the bottom half, but it takes up less than half the total area (8) 3. Primarily light - There is a splotchy, often nearly symmetrical patch of light integument found covering most of the rim and middle of the clypeus such that the majority of the clypeus is light, with the dark integument bordering the sides and area near the border with the supraclypeus (7) 4. With two large, lateral yellow lobes coming from the side of the clypeus which nearly meet in the middle, in the rare instance where the two lobes touch there is still a clear constriction between them (3) 5. Entirely light - Usually whitish or yellowish, but sometimes reddish (3)Head, hair color below the antennal sockets 1. All light (21) 2. Some dark hairs present - Dark brownish or black (14)Head, labrum, integumental color 3. All dark - The integument is entirely dark brown or black (16) 1. All light - The integument is usually yellow or whitish, although sometimes it is orangish-red (12) 2. Mixed - The integument is both light and dark, OFTEN, BUT NOW ALWAYS, the central area is light and surrounded by a dark rim (9)Head, mandible, integumental color - NOT counting the golden smear often present at the very tip 3. All black - Integument opaque and uniformly black (17) 1. Almost entirely light - Light areas OPAQUE, solidly yellowish or whitish, usually only with the tip a darker brownish or black (8) 2. Partially light - The integument is primarily dark but portions of which appear significantly lightened, these vaguely transluscent areas lightened and varying from light brown to amber in coloration, or sometimes even reddish, this color NOT appearing solid as in the opaquely light state (8)Head, mandibles, number of teeth - Note that does NOT include the tiny tooth-like bump which arises from the end of a ridge at about the midpoint of the mandible - Such a tooth should only be scored as present if it is within the apical half and clearly pointed in the form of a functional tooth 4 (22) 3 (7) 5 (6)Head, paraocular area, integumental color 1. Absent - Paraocular area completely dark (18) 3. Present, extensive - The light integumental markings in the paraocular area extend past the top of the clypeus or nearly so (12) 2. Present, limited - There is a small patch of light integument present at the base of the paraocular area, this patch usually never surpasses the midpoint of the length of the clypeus (9)Head, vertex, hair color 1. All light - Whitish to yellowish, sometimes slightly darker near the ocelli, although this slightly darkened area is still nowhere near blackish - Note that sometimes there may be very few short, blackish hairs present near the ocelli (13) 3. Mixed light and dark - With definitively DARK brown or black hairs present in appreciable numbers BUT not dominant (12) 4. Primarily dark - Most or all hairs are a darker brownish to black color (11) 2. With a darker patch directly behind the ocelli - The hair directly behind the ocelli is brownish, in direct contrast to the lighter whitish or yellowish hairs along the back of the head (9)Rear leg, tibia, scopal hair color 1. All black (22) 3. All light or nearly - Whitish to yellowish, with few if any darker hairs (5) 2. Primarily black - But with a well-defined patch of light hairs extending from the basitibial plate down the tibia far enough that they are almost always evident even without a microscope (4)Species POTENTIALLY found in the United States - Some species in this guide currently have no US records but are included due to their proximity Display all species (32) Remove the species for which there are no confirmed US records (23)Species not scored for this guide yet - Note, do not click either state of this character if you wish to include ALL species RECOMMENDED - Remove these species from the guide (29) Display species not scored (3)State or province where bee was collected AZ (27) Sonora (27) NM (16) Sinaloa (16) Jalisco (15) Michoacan (15) Nayarit (15) Oaxaca (15) Colima (14) Guerrero (14) Puebla (14) CA (13) Chihuahua (13) Mexico (13) Veracruz (13) Zacatecas (13) Baja California (12) Chiapas (12) Durango (12) Guanajuato (12) Morelos (12) Queretaro (11) Tabasco (11) Tlaxcala (10) Aguascalientes (9) Baja California Sur (9) Nuevo Leon (8) TX (8) Campeche (7) Hidalgo (7) NV (7) San Luis Potosi (7) Tamaulipas (7) Coahuila (6) Quintana Roo (6) Yucatan (6) UT (4) FL (3) OK (3) CO (2) KS (2) AL (1) AR (1) GA (1) LA (1) MS (1) Ontario (1)Subgenus Paracentris (24) Centris (5) Heterocentris (3)Thorax, mesepisternum, hair color 1. All light - If any dark hairs are present they are extremely limited, found only at the very bottom of the mesepisternum OR in very few species they are limited to right near the pronotal lobe (13) 3. Mixed, hard to tell what is dominant - There are roughly equal amounts of light and dark hair either intermixed, or with one on top and the other below (8) 5. All dark - If with any light hairs then they are restricted to the very top of the mesepisternum and do not form a distinct patch (8) 2. Primarily light - The light hairs are clearly dominant but the lower half of the mesepisternum has a significant degree of darker hairs intermixed or invading (7) 4. Primarily dark - The dark hairs extend upward from the bottom of the mesepisternum and past halfway, restricting the lighter hairs to a patch in about the top fourth of the mesepisternum (7)Thorax, scutum, hair color 1. All light - The hairs are whitish to yellowish or sometimes a light tan brown, note that at time the very TIPS of the hairs may appear slightly darkened while the rest of the hair is light - Few or no dark hairs present (22) 3. All dark - The hairs of the scutum are all black or a very dark brown, with few if any lighter hairs (6) 2. All hairs MODERATELY light- The hairs of the scutum are orangish-brown, sometimes appearing somewhat reddish - This state is best viewed without a microscope, so long as one has already been used to confirm there are no intermixed blackish hairs - Also beware that in old individuals with tattered wings the hair may have significantly faded (3)Thorax, tegula, integumental color Light - Yellowish to orangish (21) Dark - Clearly brownish, often dark reddish-brown or even blackish (15)